Tugboats dragged a rusted ship's hull down the channel on Friday and nudged it into Mormon Slough.

That part of Mormon Slough is a gritty industrial backwater sometimes used by salvagers as a floating junkyard. A clutch of old boats and cranes crowds the area.

The new arrival is the biggest dead ship. At 241 feet long, it is five-sixths the length of a football field, maybe 60 feet wide, starkly bare of all superstructure.

A man on the site identified the relic as what's left of the ferry San Leandro.

Historical sources say the San Leandro was built in 1923 for use on San Francisco Bay.

This was before the bridges. The world's largest ferry system crisscrossed the Bay among Oakland, San Francisco, Sausalito, Richmond, Tiburon, Vallejo, Berkeley and Alameda.

Commuters rode trains to the water's edge. They boarded a ferry and headed for the bar or cafe while the boat steamed across to San Francisco's Ferry Building.

I'm not sure the current system is an improvement.

With the opening of the Bay Bridge in 1936 and Golden Gate Bridge in '37, most ferries went the way of the dodo.

The San Leandro soldiered on for several owners.

During World War II, the military recruited it for use by shipyards and as a transport. After the war, Southern Pacific ran it until 1958. When SP quit the ferry business, the San Leandro was the last of its kind.

The San Leandro passed the years moored at the Ferry Building. In the 1960s, the rock group Blue Cheer lived aboard it. By some accounts, so did the Grateful Dead.

A San Francisco man named Arnold Stirewalt Gridley, a real estate broker renowned for madcap schemes, bought the San Leandro with the idea of converting it into an office building.

Gridley also bought a fleet of junked cable cars and invented the motorized cable car seen in Rice-A-Roni commercials. He held wild parties on the San Leandro while remodeling it into an office building.

Homeless people set the ship afire in 1969. Gridley rebuilt it and moved it to Pier 37. But firebrands from an adjacent pier burned it down again in the late 1970s.

Defeated, Gridley had the San Leandro towed to the Oakland Estuary and moored near the 23rd Street bridge. There it sat. Later, it was towed to Mare Island, an old folks' home for ships.

Gridley died in 2004. His heirs offered the relic to anyone who would take it off their hands.

The San Leandro passed down a chain of owners, including checkered characters and river rats. They fought a welter of court battles over ownership and unpaid costs.

The hull ended up moored in the Delta, at the northern tip of Hog Island, slowly taking on water and edging toward the bottom.

A couple of years ago, the state ordered abandoned Delta vessels to be cleared out.

By then, so many people had owned the San Leandro, or claimed to, that the State Lands Commission didn't know who to sue.

"I'm not sure who the owner is these days," admitted Peter Pelkofer, the commission's senior counsel. "I really don't give a damn. We just want 'em out of there."

The commission and the Coast Guard issued permits to a Texas salvage firm, Allied Pacific Metal, to tow the boat away.

Randeep Singh of Allied oversaw the clearing of debris from the deck, patching of the hull, refloating of the vessel and its transport to Mormon Slough.

There, an artifact from the Golden age of transbay ferries sits on death row as Singh negotiates with several shipyards to have it cut up and sold for scrap.

He can't say how long that may take.

"Time right now is of the essence," Singh said. "I can't say how much time, but we're going to do it as soon as possible."

That's sad for maritime history buffs. They argued for years that the sheer historical value of the San Leandro merited its preservation.

But all is not lost. A few of San Francisco's historic ferries are still in operation in Puget Sound.

And the Klamath, which churned between Richmond and San Rafael, was acquired by Stockton's Duraflame.

It rides on the Deep Water Channel across from Rough and Ready Island, a unique office and banquet rental, still gorgeous at 88 years young.